Abstract: In a fuel vapor release suppression system for a fuel tank, a main tank and a sub tank communicate with each other, and the sub tank and a canister communicate with each other. When the main tank has a higher temperature, fuel vapor of the main tank is supplied to the sub tank where the fuel vapor is liquefied. When the main tank has a lower temperature, fuel vapor of the sub tank is supplied to the main tank. At this time, low concentration fuel vapor is supplied from the canister to the main tank, thereby accelerating generation of fuel vapor corresponding to sub tank fuel vapor pressure, so that the sub tank fuel vapor pressure decreases. Therefore, liquefaction is accelerated in the sub tank when the main tank temperature increases. Thus, fuel vapor generated in a fuel tank is effectively liquified irrespective of ambient air temperature.

Abstract: In a fuel vapor release suppression system for a fuel tank, a main tank and a sub tank communicate with each other, and the sub tank and a canister communicate with each other. When the main tank has a higher temperature, fuel vapor of the main tank is supplied to the sub tank where the fuel vapor is liquefied. When the main tank has a lower temperature, fuel vapor of the sub tank is supplied to the main tank. At this time, low concentration fuel vapor is supplied from the canister to the main tank, thereby accelerating generation of fuel vapor corresponding to sub tank fuel vapor pressure, so that the sub tank fuel vapor pressure decreases. Therefore, liquefaction is accelerated in the sub tank when the main tank temperature increases. Thus, fuel vapor generated in a fuel tank is effectively liquified irrespective of ambient air temperature.

Abstract: In a control apparatus for a hybrid vehicle having an engine and a motor as a driving source, the control apparatus stops fuel supply to the engine by a fuel supply stop device during deceleration, and performs regenerative braking by the motor depending on the deceleration state, wherein the engine is a type of engine capable of executing cylinders deactivated operation for at least one cylinder, and the control apparatus comprises the cylinders deactivated operation execution flag F_ALCS for determining whether it is appropriate for cylinders to enters into the deactivated operation based on the traveling conditions of a vehicle and a variable valve timing mechanism for deactivating the operation of the cylinders of the engine when the cylinders deactivated operation is determined.

Abstract: An engine control system for hybrid vehicles, so as to smoothly switch the driving operation from the cylinder-deactivated engine operation, in which at least a part of the total number of cylinders of the engine is deactivated, to the all-cylinder-activated engine operation while considering the driver's intention. When the vehicle is decelerated, the cylinder-deactivated engine operation is performed and regeneration using the motor is performed. The system includes a cylinder deactivation release determining section for releasing the cylinder-deactivated engine operation when an engine speed decreases to a reference engine speed with respect to the cylinder-deactivated engine operation; and a brake operation detecting section for detecting whether a brake pedal is depressed.

Abstract: In an assist control apparatus for a hybrid vehicle comprising an engine as a drive source of the vehicle, and a motor assisting drive of the engine in accordance with driving conditions of the vehicle, the engine is a cylinder deactivating engine switchable between a normal operation and a cylinder deactivating operation, and there is provided a cylinder resumption assist judgment device which judges whether the drive of the engine should be assisted by the motor, when the engine shifts from the cylinder deactivating operation to the normal operation, and when the cylinder resumption assist judgment device judges a resumption from the cylinder deactivated condition, and judges that a throttle opening is larger than a predetermined value, drive of the engine is assisted by the motor.

Abstract: A hybrid vehicle control apparatus is provided which can improve fuel consumption. There is provided: a cylinder cut-off determination section for determining whether all cylinders should be cut off; a cylinder cut-off cancellation determination section for determining whether cylinder cut-off cancellation conditions have been satisfied; a cylinder cut-off execution section for operating a spool valve when the cylinder cut-off determination section determines that cylinder cut-off is possible; and a cylinder cut-off control section for cutting off the cylinders of the engine based on the operating conditions of the cylinder cut-off determination section, the cylinder cut-off cancellation determination section and the cylinder cut-off execution section.

Abstract: An engine control system for hybrid vehicles, so as to smoothly switch the driving operation from the cylinder-deactivated engine operation, in which at least a part of the total number of cylinders of the engine is deactivated, to the all-cylinder-activated engine operation while considering the driver's intention. When the vehicle is decelerated, the cylinder-deactivated engine operation is performed and regeneration using the motor is performed. The system includes a cylinder deactivation release determining section for releasing the cylinder-deactivated engine operation when an engine speed decreases to a reference engine speed with respect to the cylinder-deactivated engine operation; and a brake operation detecting section for detecting whether a brake pedal is depressed.

Abstract: In an assist control apparatus for a hybrid vehicle comprising an engine as a drive source of the vehicle, and a motor assisting drive of the engine in accordance with driving conditions of the vehicle, the engine is a cylinder deactivating engine switchable between a normal operation and a cylinder deactivating operation, and there is provided a cylinder resumption assist judgment device which judges whether the drive of the engine should be assisted by the motor, when the engine shifts from the cylinder deactivating operation to the normal operation, and when the cylinder resumption assist judgment device judges a resumption from the cylinder deactivated condition, and judges that a throttle opening is larger than a predetermined value, drive of the engine is assisted by the motor.

Abstract: A hybrid vehicle control apparatus is provided which can improve fuel consumption. There is provided: a cylinder cut-off determination section for determining whether all cylinders should be cut off; a cylinder cut-off cancellation determination section for determining whether cylinder cut-off cancellation conditions have been satisfied; a cylinder cut-off execution section for operating a spool valve when the cylinder cut-off determination section determines that cylinder cut-off is possible; and a cylinder cut-off control section for cutting off the cylinders of the engine based on the operating conditions of the cylinder cut-off determination section, the cylinder cut-off cancellation determination section and the cylinder cut-off execution section.

Abstract: In a control apparatus for a hybrid vehicle having an engine and a motor as a driving source, the control apparatus stops fuel supply to the engine by a fuel supply stop device during deceleration, and performs regenerative braking by the motor depending on the deceleration state, wherein the engine is a type of engine capable of executing cylinders deactivated operation for at least one cylinder, and the control apparatus comprises the cylinders deactivated operation execution flag F_ALCS for determining whether it is appropriate for cylinders to enters into the deactivated operation based on the traveling conditions of a vehicle and a variable valve timing mechanism for deactivating the operation of the cylinders of the engine when the cylinders deactivated operation is determined.

Abstract: An oxygen concentration sensor abnormality-detecting system is provided for an internal combustion engine having first and second oxygen concentration sensors arranged in the exhaust system upstream and downstream of a catalytic converter therein. An ECU determines that the first oxygen concentration sensor is functioning abnormally if an output from the first oxygen concentration sensor does not change when an output from the second oxygen concentration sensor changes.

Abstract: A catalyst deterioration-determining system for an internal combustion engine has a catalyst arranged in the exhaust system, for purifying exhaust gases emitted from the engine, an oxygen concentration sensor arranged in the exhaust system at a location downstream of the catalyst, for detecting the concentration of oxygen present in the exhaust gases, and an ECU which controls the air-fuel ratio of an air-fuel mixture supplied to the engine in a feedback manner in response to the output from the oxygen concentration sensor. Determination of deterioration of the catalyst is carried out based on the output from the oxygen concentration sensor during execution of air-fuel ratio feedback control.

Abstract: A system for detecting failure of a fuel pressure sensor in an internal combustion engine, including an injector (32) provided at an intake system of the engine downstream of a throttle valve (38), a fuel supply passage (16) connected to a fuel supply source (fuel tank 12) for supplying fuel to the injector (32), pressure regulator (28) provided in the fuel supply passage (16) and operating to maintain a difference between the fuel pressure (PF2A) and the manifold absolute pressure at a constant value, a fuel pressure sensor (PF2 sensor 54) for detecting the fuel pressure (PF2A) in the fuel supply passage (16) downstream of the pressure regulator, and a manifold absolute pressure sensor (62) for detecting the manifold absolute pressure (PBA) downstream of the throttle valve (38). In the system, an index indicative of a ratio (.DELTA.PF2A) of the fuel pressure (PF2A) fluctuation relative to the manifold absolute pressure (PBA) fluctuation is compared to reference values (#PF2L, #PF2H) which define a range.

Abstract: An air-fuel ratio control system for an internal combustion engine includes an ECU which cuts off fuel supply to the engine at deceleration thereof, measures a fuel cut-off period over which the fuel cut-off means cuts off fuel supply to the engine, and enriches the air-fuel ratio of a mixture supplied to the engine to a degree dependent upon the measured fuel cut-off period, at the restart of fuel supply to the engine immediately after termination of cutting-off of fuel supply to the engine.

Abstract: Supply of fuel is stopped when fuel pressure sensed by a pressure sensor provided upstream of a regulator is at a predetermined value or less to avoid abnormal combustion caused by improper adjustment of air/fuel ratio. Even slight variation of the fuel pressure is sensed by monitoring the fuel pressure in an interval after closing a fuel shut-off valve once opened to re-opening of it. In addition, an abnormal state in the fuel system is detected by comparing an accumulated value of amount of injected fuel and an estimated value of fuel consumption in the tank. Furthermore, the peak current value of the fuel injection valve is controlled so that, when the engine at a low temperature is started, lift load of the injection valve is larger than sticking force of the injection valve, thereby preventing such situation where the injection valve is frozen so that it cannot supply fuel to the engine. In this case, the engine can be smoothly started by simultaneously controlling the valve open time.